Grinding mill



April 25, 1933. c. E. WuENscH 1,905,545

GRINDING MILL April 25, 1933. c. E. wUENsCH 1,905,545

GRINDING MILL Filed March 6, 1951 2 Sheets-Sheet 2 Qffgl 6+ #s 46 A g43.

Patented Apr.A 25, 1933 UNITED STATES camas aan WUENSCH, F JOPLIN,MISSOURI, AISSIGN'OR TO BENEFICIA- TION INCORIEORAJJEIID, A.CORPORATION. QF DELAWARE i @BINDING HILL Application inea. meas', 1931..smal inagzsaoasasf Thisy invention relates to grinding mills,l and morevparticularly to a grinding mill of the ball type in which balls orequivalent\ means are employed for effecting the .grinding)operation. v

- ne of the main objects of my invention is to provide a grinding millof simple con-r struction and high efficiency. A further object is toprovide novel means for removingt D from the mill, during 'operationthereof, the

' fines or slimes during the grinding operation and producedthereb'y."-It is also an object of my invention to yassure thoroughagitation of the balls and the material being round without interferingwith the grind- 111g operation to a material extent. A further object isto assure proper travel.f of the grinding balls in a predeterminedmanner such as to effect maximum efficiency in the grinding operation.Another object is to provide a grinding bowl of novel constructi0n` suchas to assure this desired travel of the grinding balls. Further objectsand advantages of my invention will appear from the detaileddescription.

In the drawings:

Figure 1 is a plan view of a grinding-mill constructed in accordancewith my invention;

' Figure 2 is a section taken substantially on line 2-T2 of Figure 1; l

Figure 3 is a central vertical sectional view through a modified form ofthe mill adapted for use as a disintegrator;

Figure 4 is a vertical sectional, view through the take-0E pipe and thescreen therefor and associated part;

Figure 5 is a section taken substantially on line 5-5 of Figure 4; and

Figure 6 is a vertical sectional view through a modified form of screenand associated parts, parts being shown in elevation.

My mill includes a grinding bowl 1 mounted to rotate on a vertical axis.is conveniently formed of abott'om plate 2, lower and upper sections 3and 4, respectively, and a top section 5. The bottom plate and thesections of the bowl are provided with suitable interengaging rabbetsand projections forming step Joints, and with out- 0 wardly projectingflanges which receive bolts This bowl for securinthe sections and thebottom `plate together. gear ring 6 extends about section '4 and isbolted or otherwise suitably secured -thereto This gear -ring operatesbetween upper and lower ball bearings .7' and 8, re'- spectively, thelatter bearings'being suitably supported by a base 9 formed of concreteor other'suitable material, this base being preferably continuous and ofannular shape in plan, employed or supporting the lower bearing ifdesired. The upper bearing is supported by means of brackets 10 suitablyanchored to the base 9 and extending upwardly over the gear ring, theupper race of the upper ball Ibearing 7 being suitably secured to thesebrackets. The two sets of ball bearings provide antifriction bearingsfor the bowl and also serve to prevent any tendency of the bowl to tipor rock during rotation thereof. For rotating .the bowl'I- provide asource of power,such as an electric motor 11 of suitable type. A pulley12 is keyed upon the shaft of this ymotor'and is connected by a belt 13to a pulley 14 keyed upon drive' shaft 15. This shaft 15 is rotatablymounted in suitable bearing members 16 anchored to extensions 17, in thenature of piers, projecting vfromthe base 9. These extensions may beconnected at their outer ends to provide a pier 18 upon which the motor11 is suitably mounted. Shaft 15 is provided with a worm 19 suitablysecured thereon and meshing with the gear ring 6. Preferably, a wheel20, of considerably greater diameter than the pulley 14, is secured uponone end of shaft 15. This wheel is provided with suitably dis-`posedopenings 21 for reception of a bar or similar tool. This providesconvenient means whereby a great leverage effect can be obtained forturning the bowl 1- lnanually, for the purpose of loosening and breakinup though suitably spaced piers may bematerials which have dried withinthe owl to such an extent as to become vcemented together and to thebowl and associated members, dueto the mill being out of operation foran appreciable period of time withthe break up the materials, it is thenrotated by means of the motor 11 and associ' ated gearing. The bowll isrotated atrelavtivelyhigh speed, which increases the rate andeffectiveness of the grinding operation. Any other suitable or preferredmeans mayr beem lo ed for rotating the bowl, and any ,suitab e rivingconnectlon between the mol son. V

' and f so suitabl 26. T

. tor lland shaft 15 may be employed. f u' The bowl 1 may be providedwith a suitable liner, if desired, though such a linei` has been omittedfor clearness of illustration. Also, the balls and the material tobeground have been omitted, for the same rea- Referring moreparticularly to Figure 2, it will be noted that the interior of the bowlis ofv approximately elliptical shape in transverse vertical' section.rl `he linner surface of the surrounding wall of the bowl is i ofarcuate shape in vertical section, the mid-.

portion .of-the arc being at approximately the centralhorizontal planeof the bowl so that the inner surface thereof curves upwardly andoutwardly of the bowl at its lowerv portion.r and then upwardly andinwardly of the bowl at its upper portion. f The top portion of topsection curves inwardly rovidesa lip 22 which projects' inward yof thebowl and defines an opening` 23 through the top thereof. When the millis loaded with lgrinding balls and is standing still, the` top line ofthe charge of balls Each o f these members is provided, at itsV upperend, with an enlargement 3 0 which 1s suitably bored and threaded forreception of the lower portion of a capstan screw 31 which passesthrough, but is free from, beam 26 "rand flange. 28. A n ut 32 screwsupon screw 31 and bears upon the upper face of beam 26, this nutcooperating with the screw for securing supporting member-29 inadjustment. By loosenin thecapstan screw' 31, the supporting member-29can beturned about the screw to a'desired extent,gafter whichenlargement 30 of this member is 6- forced against the ange 28, by-meansof the capstan screw and nut .32, so as toeffectlvely lock member 29 inadJustment.

in members 9 I provide a-.deflector'33 suit- 5 aby secured thereto. 1'This c leflector is in s bracket is provided,- atthe clined to thevertical and is also inclined transversely of the bowl, the degree ofthe latter inclination beingcontrolled by the ad.- justment of thesupporting member 29. As

be noted more clearly from Figure 1,l

the deflectors 33 are oppositely related, the

downward inclination thereof/being counter -ends ofthe deliectors areconnected by a brace member'34 suitably shaped to extend about atake-olf pipe435 extending through the center of bottom plate 2.-

The take-off pipe 35 is suitably secured through bottom plate 2 forrotationY with the bowl, and extends upwardly within the bowl centrallythereof, this pipe opening into the bowl remote from the bottom of theVsame.

The pipe 35 discharges into a funnel 36 which serves to 'direct thedischarged material intora pipe line or launder 37, `by means Vof whichthe material is conducted to suitable receptacles for storage or forfurther treatment, as conditions mayrequire. Y

Referring more particularly to Figure 4, a screen 38 extends about the uper portion of pipe 35.v Ihe upper end o this screen is convenientlysecured to an enlargement 39 .ofa rod 40 slidablv mounted through beam26. A reduced rod'41 depends from enlarge-- ment 39 and is provided, atits lower end,

with a spider 42 the arms of which are slidably mounted through slots 43in pipe 35 and extending from theupper end thereof. The screen issuitably secured to this spider, and extends downwardly beyond the sameabout pipe 35 in spaced relation thereto, the lower end portion of thisscreen fitting snugly about the pipe below the lower ends of the slots43, as at 44. Since' the enlargement 39 is of less diameter than thepipe 35, the up# V `per portion 45 of the screen is. of frusto-conicalshape, which is advantageous as facilitating passage of the-'finelyground materialsthereto. A guard 46 is bolted orotherwise suitablysecured to bracket 27, and extends v downwardly about'the screen 38 inspaced relation thereto, this guard being provided with slots47 thereinto facilitate admission to the screen of the finely ground materialswhich it is desired todischarge through the pr'pe 35,4 -The slots 47`may be of any desired width, provided they arel not suiiciently Wide to`permit of the with registering openings which accommo grinding ballsstriking the screen fand causing injury thereto. A The,-l bracket'27 andthe guard 46 are provided At the lower end of each of the support---`operate with a ratchet disk 49 which screws upon the upper portion ofrod 40 and is adjustably secured thereon in a suitable manner, as bymeans of a set screw 50. During rotation of the bowl 1, pipe 35 rotatesthere.

f with and the screen 38 and rod 40 rotate with the pipe due to theengagement of the arms of the spider 42 into the slot 43of the pipe.Since ratchet disk .49 is lined to rod 40, it rotates with this rod andthe teeth of this ratchet disk coact with the contacting surfaces of theratchet pins 48 for Vcausing vertical reciprocation of the screen athigh speed. In this manner the screen is vibrated and possibility Aofclogging thereof is eliminated. Under ordinary conditions, the vmesh ofthe screen may vary from to 65 mesh, though the mesh of the screen willdepend upon the material being ground and may be Varied withinfwidelimits.

In Figure 6, I 'have illustrated a modified form of means for vibratingor reciprocating the screen. A spider 51 is suitably secured to theupper end of pipe 35-for rotation therewith. The upper end of screen38is suitably secured to a neck 52 depending from a ratchet head 53. I Arod 54, of squared or other suitable non-circular cross section, issecured at its upper end in neck 52, and is slidably 'mounted through anopening at the center of spider 51; and corresponding to the crosssection of the rod. An extension coil spring.

A 55 is disposed about rod 54` and is confined between the spider andneck 52. This spring yieldingly urgesratchet head 53 toward acooperating ratchet head 56 secured upon the lower end of a rod 57. Theupper portion of circular cross section and is slidablethroug-h acorresponding opening .in thel upper end the bowl 1 isl rotated in aclockwise' direction, Vas indicated in Figure 1, the ratchet head 53 ofa sleeve 58 which ,screws through cross beam 26 and is secured inadjustment there- 'l in byl a jam nut 59. An extensionfcoil spring 60ismounted about rod 57 and is confined between the upper end of sleeve 58and a nut 61 which screws upon the'lower portion of rod 57. This nutprovides convenient means for adjusting the tension of spring 60.y Whenis similarly rotated and the teeth of this ratchet head cooperate withthe teeth of ratchet head 56, and the springs 55 and '60, for impartingvertical reciprocation to the screen 38 for vibrating the'latterf As hasbeen above indicated, and as will be apparent to those skilled in theart, various mean's'may be employed for vibrating the screen; Ido-- not,therefore, lintend to in Aany way limibmy invention to the particularmeans disclosed- "for vibrating the screen, since any suitable orpreferred means, other than the means Aherein disclosed, may be employedfor this purpose.l

this rod is of squared or other suitable noni `be ground, it is rotatedl Preferably the inner surface of the bowl is laidout on the spiral ofArchimedes, both considered in horizontal section and in vertic alsection, so .that the materials in the bowl tend Ato travel at-aconstantispeed for every degree of angular rotation thereof. Thistendency of travel-of the material, including by the defiectors 33.While the bowl is preferably laid out on the spiral of Archimedes, thisis not essential and the shape of be suspended a suitable hoist 65, oran electromagnet 66, optionally. When the magnet is not in use it may besuspended from the beam 63 adjacent one end thereof, as shown, and

lthe grinding balls, is modified to some extent' when the hoist is notin use it may be susl pcnded from the bea-m in the same manner as themagnet. The magnet, in conjunction with .the trolley 64, providesconvenient means for removing the `balls from"the mill,-

when desired or necessary, and placing them in a suitable hopper 67.supported above and to one side of the bowl. This hopper is pro.- videdwith an inclined chute 68, which may have any suitable removable'vclosure means associated therewith, the chute being dlsposed to directthe balls from the hopper 67v into the vbowl 1 when the chute is opened.The hoist 65 provides means for handling parts of the bowl andassociated structure.

Whenthe bowl l has been suitably charged with the grinding ballsv andthe material to at high speed in the manner previously described. In therotation of the bowl, thev grinding balls and the heavier pieces ofmaterial to be groundlare` urged outwardly by centrifugal force intocontact with the surrounding wall of the bowl.

After thej'mill has been in operation for a short time, the innerlsurface thereof is, in effect, covered with a layer of grmdmg ballsover. which the remaining balls and material in thel bowl' 1 m'oveduring the grlnding opface vof the bowl, combined with the centrifugalaction due to rotation thereof, the balls tend to move upwardly alongthe mner face The then displaced or pushed inwardly of the bowl bythefollowing balls and material',-

eration. Due'to the curvature ofthe inner andare discharged from the lipdownwardlyr y and inwardly toward theI center of the bowl. In thismanner, the material to be ground and the balls .tend to travel -fromthe bottom or lower portion of the bowl outwardly and then.

60 .wardthe central-dischargepointby the acupwardly along the inner faceof the bowl and then are discharged downwardly toward the center of thebowl, so that such material and the balls tend to travel through anf'approximately elliptical path. This travel of the balls and the materlal,however, is modified by the dellectors 33. `The yballs and the materialat the lower portion of the bowl are deflected upwardly and inwardly ofthe bowl, by the deiiectorsl 33, and are delivered at the centralportion of the bowl, from which these balls and the material are movedoutwardly by centrifugal force into contact with'the layer of balls atthe'inner face of the bowl.I The travel of the material and the ballswhich travel over the layer of balls at the inner face of the bowl,instead of being approximately elliptical is through a pathapproximately in the form of the figure 8. This assures thoroughcommjngling of the balls and the material to be ground with the resultthat "gh eiiiciency in the grinding operation is obtained. Y

As the grinding operation continues, the heavier particles of materialand the balls are thrown outwardly by centrifugal force and the lighterparticles of material which has been ground, and which may be referredto as the nes for purposes of description, is crowded toward the centerof the bowl at the upper portion of the mass, where it tends toaccumulate. As these fines accumulate, they pass through the slots inguard -46 .and through the screen 38, entering the pipe 35 through theupper end thereof and through the slots 43 lwhen such slots areprovided. These fines then pass downwardly through pipe 35, by gravity,into the funnel 36 and thence to the llaunder 37. This mill is adaptedeither for dry grinding or wet grinding. The material to be ground isfed into the bowl a3 required, and, when wet grinding, water 'is alsofed intothe bowl' as required. In the latter case, when wet grinding,the fines which would be produced inl dry grinding form, with the water,slimes, which pass through the screen V38 into pipe 35 and thence intothe funnel 36 and launder 37. By this construction I provide extremelysimple and highly efficient means whereby the fines or slimesareeparated from the remainder of the mass of material 'in the bowl,during the grinding operation, and are taken off by gravity as theyaccumulate at the central portion of the bowl. This I consider of valueas contributing to the eiiciency as well as the simplicity ofconstruction and operation of the mill. A further advantage o f my`construction is that the f finest ground material in the mill iscrowded or urged` totion of the coarser materials, duringV the grindingoperation, the most finely ground materialbeing removed as itaccumulates. This prevents excessif-7e grinding, such as 'the mill the?7section 71 o LegnameA p encountered in ball mills of ordinary type,

with the -result that the material is ground more -uniformly and has aminimum amountv of colloidal forms. This is advantageous as greatlyfacilitating subsequent treatment of the ground material. Since the bowlis open at its top,- the grinding 'operation can be watched at all timesand the rate of feed of the material and water, the amount of balls, thespeed of rotation of the bow1,and the angle of deflection of thedeflectors, can be controlled in such manner as to effect the mosteflicient result. A further advantage of my construction is that nobrokenor -worn dow-n balls are discharged from the mill, so that theballs are completely consumed in useful grinding work.

Since the deiectors 33 are spaced away from the surrounding wall of thebowl 1, and

4.are free from this wall, they do n ot seriously interfere with thecirculation vof the balls and -material within the bowl, nor do theyinterfere with formation of the layer of balls at the inner surface ofthe bowl previously referred to. These deiiectors assure thoroughagitation of the b alls and the material in the. lower portion ofthebowl, but are so adjusted as not to present objectionable resistance tocirculation of the balls and the material, this adjustment beingeffected with facility by means of the capstan screws 31 and associatedparts in the mamier previously described.

It is desirable that suitable means be provided whereb the bowl canconveniently be washed out afyter completion of the grinding operation.For this purpose, l? provide a suitable opening through lower section 3of the bowl, -this openingbeing normally closed by a removable plug 70,or other suitable means, bolted or otherwise suitably secured tosection3. After completion of the grinding operation, the plug 70 may beremoved and the interior of the bowl andV the parts therein may 'bethoroughly washed' and flushed out, the water and the mjateriallinsuspension therein passing through the opening referred to.

A The .bowl of my mill is also well adapted for use as a disintegrator.For this purpose, the sections stand 5 may be replaced-by an upper ortop section 71 which is curved outwardly and reversely to the lowerportion of thebowl so as to provide an outwardly extending anddownwardly curved lip 72. An annular sloping launder 73 extends aboutthe bowl and beneath the lip 7 2 for'receiving'materials dischargedtherefrom. When using the mill as a disintegrator, no grinding balls arenecessary, the residual .nodules in the materialitself servin to causethe desired 'disintegration thereo` during the rotation of the bowl.

move upwardl over the top the bowl and t entravelover As these nodulesaccumulate in .i so

- are not employed.

`to deflect materials in the vlower collects at the central portionv ofthe bowl and is taken olf through the take-olf as before. The "deiectors33 may uire. Also, if desired, the screen 38 over t e upper portion ofpipe 35 ma be employed although, under ordinary con `tions, this is notnecessary. It is apparent, therefore,

that the bowl of my invention while ordinarily particularly adapted foruse as a grinding mill employing grindin balls, can readily be convertedinto a bow suitable for use as a'disintegrator in which the grindingballs As above indicated, and as will be apparent to those skilled inthe art, changes in construction and arrangement of parts of myinvention may be resorted to without departing from the field and scopeof the same, and I intend to include all such variations, as fall withinthe scope of the ap ended claims, inthis application in which t eypreferred forms only of my invention are disclosed.

What tI claim is:

1. In a grinding machine, a bowl mounted for rotation on a verticalaxis, the interior of said bowl being of approximately elliptical shapein transverse vertical section, deflecting means within the bowl anddisposed Y p ortion of the bowl upwardly and toward t e central portionof the bowl durinur rotation thereof, and a take-off pipe openm into thebowl centrally and remote from t e bottom thereof and disposed totakeoff by gravity fines gcculmulated at the central portion of the 2.In a grinding machine, a bowl mounted for rotation on a vertical axis,the interior.

of said bowl being of approximately elliptical shape in transversevertical section, de

iiecting means within the bowl and disposed to deflect materials in thelower portion of the bowl. upwardly and toward the central portion ofthe bowl during rotation thereof, and a take-off pipe extending throughthe bottom of the bowl centrally thereof and opening into the bo`wlremote from the bottom of the same for taking oif by gravity finesaccumulated at the central portion of the bowl.

3. lIn a grinding machine, a bowl mounted for rotation on a verticalaxis, the vinterior of said bowl being of approximately elliptises calshap'e in transverse vertical section, detlectin means within the bowland disposed to de ect materials in the lower the bowl upwardly andtoward t e central portion of the bowl during rotation thereof, atake-olf ipe extending throu h the bottom of the wl centrally thereo andopen'- ing into the bowl remote from the bottom or not, as desirable 6ras conditionsmay rertion of i -lectors mounted upon said members andinclined transversely of the'bowl and to the vertical, said deiiectors'.being oppositely related -and disposedto deflect materialswithin thelower portion of the bowl upwardly and to'ward the central portionthereof during rol tation of said bowl, and a take-off pipeldisposedbetween the delectors and openingl through the bottom of the bowlcentrally thereof, said pipe opening into the bowl centrally and remotefrom the bottom thereof for taking olf by gravity fines accumulated atthe central portion of the bowl.

5. In a grinding mill', a bowl mounted for rotation `on a vertical axis,a take-olf pipe openi through the bottom of the bowl centrally t ereofand opening into thev bowl remote from the. bottom of the same fortaking off by gravity fines produced in the grinding operation, thelower portion of the surrounding wall of the bowl being curved upwardlyand outwardly and the upper portion of said wall beingl curved outwardlyand reversely to said lower portion and forming a downwardly curved lipat the top of the bowl for discharge of materials therefrom, and alaunder extending about the bowl beneath said lip for reception ofmaterials discharged therefrom.

6. In a grinding mill, a bowl mounted for rotation on a vertical -axisand a take-olf pipe opening through the bottom of the bowl centrallythereof and opening into the bowl remote from the bottom of the same fortaking oil by gravity fines produced in the grinding operation, thelower portion of the surrounding well of the bowl being curved upwardlyand outwardly and the upper portion of said wall being curvedoutwardlyand reversely to said lower portion and forming a downwardlycurved lip at the. top of the bowl for discharge of materials therefrom.

In witness whereof, I hereunto subscribe e

